Coral bleaching is a major problem for ocean ecosystems as the ocean gets warmer. Researchers at Stanford have found a new method for regenerating bleached corals.

Scientists working on coral found that when they had a bleached and healthy example accidentally touching in the lab, the symbionts from the healthy coral that make its food were able to spread to the bleached coral, reviving it in a matter of weeks. Contact was only required for one week, although three days was sufficient in a few cases. The effect only seems to work with corals of the same genet as the healthy corals of other genets just take over the bleached coral antagonistically.

This is particularly exciting, as areas where not all coral has bleached may indicate the presence of symbionts that are more heat tolerant, and being able to spread these symbionts to their neighbors quickly can greatly speed up the process of coral regeneration and save the reef. Coral reefs are some of the most vibrant ecosystems in the ocean, so if you save the coral, you can save many other species as well that rely on them.

If you’d like to explore how the coral is doing near you, perhaps you should try an open ROV or a bionic jellyfish?

Although solar panels may seem like a kind of magic, they’re really quite simple devices, in their silicon form featuring nothing but the p-type silicon wafer and an n-type layer doped with e.g. phosphorus. Because of this simplicity it’s quite possible to make your own solar cells at home using only a few basic, off-the-shelf ingredients and a kiln, which in this recent video by [Dr. Semiconductor] uses a microwave kiln and thus justifies the video’s title.

Even the silicon wafer that you start with can be easily purchased online, though you have to be careful that it’s a bare wafer, without existing etchings on it. On this you need to get a phosphorus-rich layer, which is done by creating a delicious mixture of 1 mL of tetraethyl orthosilicate (TEOS), 0.3 mL of 85 wt% phosphoric acid, 5 mL of ethanol and 0.25 mL of distilled water. After low heat boiling this for 30 minutes, it is spincoated onto the cut square of silicon wafer using a spinning platform, like a PC fan.

Next, you shove the coated silicon into the kiln and put it into the microwave to bake at a fairly low power level for half an hour. In the video it took less than 50% power of the microwave to not melt the silicon, so remember that those microwave kilns get pretty hot.

With the delightful smells of freshly baked silicon now teasing your nostrils, you can then take out the doped silicon to sand or etch off the thin layer of glass that’s formed around the new PV cell. On the clear spots you can now put a gallium-indium contact on the p-type Si side and a wad of indium on the newly doped Si-P side, which are now your contacts for the PV cell.

The full recipe along with many of the issues discussed in the video can also be found on the blog article, though the video conclusion notes that many improvements are still possible. The created PV cell in the video reaches an efficiency of about 5%, but this could be improved through changes like the use of a clean-room, adding an anti-reflection coating and improving the contact with the cell.

In countries where PET bottles do not get slapped with an additional fee that induces you to return it for recycling and said fee back, the resulting piles of discarded bottles have led many enterprising individuals to consider using them to make their own PETG filament. One big question of course is just how much work it is to create even a single 1 kg spool of PETG, which is a question that [PETCraft] was only too happy to answer in a recent video.

With the channel owner clearly living in a country without a bottle deposit, it’s very easy to see PET bottles strewn about as trash, including multi-liter water bottles. As a very recycling-focused channel, this provides an excellent opportunity to show how they go about recycling these into filament.

The detailed process is covered in previous videos in the channel, but essentially they are first heat-smoothed to make them much easier to cut into thin strips. This is done with a very DIY cutter – also constructed from mostly salvaged and other common parts – before the strips are passed through the heated extruder nozzle of the DIY filament extruder before being wound onto spools.

Ultimately it took thirteen 5 liter bottles, a 10 L, two 8 L and a single 1.5 L bottle to hit the 1 kg target, which is quite an impressive amount of work. The next challenge will be to actually print with it, which will – naturally – be done with a DIY 3D printer made from salvaged parts and an Arduino board.

The good news about recycling bottles like this into filament is that basically all PET bottles will actually be PETG anyway, as the glycol adds the flexibility that’s essential in water bottles so that they do not shatter or rip easily. The real question you have to ask yourself is whether cleaning, cutting and spooling dozens of bottles is worth saving perhaps 10-20 bucks on a commercial spool of 1 kg PETG filament.

There’s one thing [Silent H] wants you to know before you watch his video about making biodiesel, embedded below: he started this project before he’d even heard of the Strait of Hormuz. No, he’s just independent-minded and wanted to try making his own fuel when diesel was– in retrospect– cheap as chips. That’s probably a good thing, because while [Silent] gets his pint of fuel at the end of the video, it’s not from algae; it’s from a backup crop of sunflowers.

As it turns out, he picked what was the perfect algae and the absolute worst algae for making biodiesel from: Chlorella Vulgaris. It’s perfect because it’s easy to grow, and easy to extract from the growth medium, as it sinks when it is ‘ripe’, and has a very high oil content. Of course [Silent] didn’t want to toss algae cakes into a steam powered canoe, he wanted diesel fuel for his vehicle. That’s where the project broke down: Chlorella Vulgaris cells are exceptionally tough, and if you can’t rupture the cell wall, you can’t can’t get out any appreciable oil. A few grams by solvent extraction is all he manages before switching to more tractable feedstock.

That feedstock is sunflowers, which give up their oil through the application of violent pressure. That is to say, he crushes the seeds in an oil press. Oil acquired, he goes on to transesterfy the stuff, extracting glycerine to produce biodiesel– a process ripe for hacking that you’d think we’d cover more often.

We have covered the algae growth side of things before, but that algae seemed to be destined for other uses than fuel.